Voice-activated personal alarm

ABSTRACT

A voice-activated personal alarm includes a satellite global positioning receiver, a specific danger sensor, a voice activation circuit, and a radio transmitter. In a specific embodiment, the satellite global positioning receiver relies upon the U.S. Global Positioning System (“GPS”). In another specific embodiment, the radio transmitter is provided by a wireless telephone using an existing wireless communications network and therefore also provides a two-way voice communication channel. In a specific embodiment of the invention, a distress phrase such as “HELP!” spoken into a microphone is recognized and activates the radio transmitter to transmit the current global location. In another embodiment, the detection of a specific danger by the danger sensor also activates the transmission of the current global location.

This Patent Application is a continuation-in-part of U.S. patentapplication Ser. No. 09/325,030, filed Jun. 3, 1999, now Pat. No.6,198,390, which was a continuation of U.S. patent application Ser. No.08/849,998 filed Jul. 6, 1998, now U.S. Pat. No. 5,963,130, which was aNational Stage entry from International patent application Ser. No.PCT/US96/17473, filed Oct. 28, 1996; and claims priority from U.S.patent application Ser. No. 08/547,026, filed Oct. 23, 1995, now U.S.Pat. No. 5,650,770, which was a continuation-in-part of U.S. patentapplication Ser. No. 08/330,901, filed Oct. 27, 1994, now U.S. Pat. No.5,461,365. Therefore, portions of this Application claim priority fromOct. 27, 1994, other portions claim priority from Oct. 23, 1995, otherportions claim priority from Oct. 28, 1996, and the remaining portionsclaim priority from the filing date f this application.

TECHNICAL FIELD

This invention relates to personal alarm systems and in particular toportable, self-locating, voice-activated personal alarms.

BACKGROUND ART

Personal alarms are known. They detect the presence of a specific dangerand provide a signal for giving an alarm and for summoning help. It isalso known to transmit the danger detection signal via a radiotransmitter to a common base station which supervises multiple personalalarms. It is also known to use a wireless telephone communicationssystem for that purpose. The incorporated references disclose a class ofportable, self-locating personal alarms which include a satellite globalpositioning receiver for providing an accurate location of the monitor.These disclosed devices do not disclose a voice-activated device. It isdesirable to provide such capability.

DISCLOSURE OF INVENTION

The need is met by the present invention which incorporates a satelliteglobal positioning receiver, a specific danger sensor, a voiceactivation circuit, and a radio transmitter. In a specific embodiment,the satellite global receiver relies upon the U.S. Global PositioningSystem (“GPS”). In another specific embodiment, the radio transmitter isprovided by a wireless telephone using an existing wirelesscommunications network and therefore also provides a two-way voicecommunication channel. In a specific embodiment of the invention, adistress phrase such as “HELP!” spoken into a microphone is recognizedand activates the radio transmitter to transmit the current globallocation. The detection of a specific danger by the danger sensor alsoactivates the transmission of the current global location.

BRIEF DESCRIPTION OF DRAWINGS

For a further understanding of the objects, features and advantages ofthe present invention, reference should be had to the followingdescription of the preferred embodiment, taken in conjunction with theaccompanying drawing, in which like parts are given like referencenumerals and wherein:

FIG. 1 is a block diagram of a personal alarm system in accordance withone embodiment of the present invention and transmitting at selectablepower levels.

FIG. 2 is a block diagram of another embodiment of the personal alarmsystem illustrated in FIG. 1 including multiple remote units.

FIG. 3 is a block diagram illustrating another embodiment of thepersonal alarm system in accordance with the present invention.

FIG. 4 is a pictorial diagram illustrating a preferred message formatused by the personal alarm system illustrated in FIG. 2.

FIG. 5 is a pictorial diagram illustrating another preferred messageformat used by the personal alarm system illustrated in FIG. 2.

FIG. 6 is a block diagram illustrating an embodiment of the personalalarm system of the present invention using the Global PositioningSystem to improve remote unit location finding.

FIG. 7 is a pictorial diagram illustrating a base station and remoteunit of the personal alarm system of FIG. 1, in a typical childmonitoring application.

FIG. 8 is a pictorial diagram illustrating a remote unit in accordancewith the present invention being worn at the waist.

FIG. 9 is a pictorial diagram illustrating a mobile base station inaccordance with the present invention for operation from a vehicleelectrical system.

FIG. 10 is a pictorial diagram illustrating a base station in accordancewith the present invention being operated from ordinary household power.

FIG. 11 is a block diagram illustrating a man-over-board alarm system inaccordance with one aspect of the present invention.

FIG. 12 is a block diagram illustrating another embodiment of theman-over-board alarm system.

FIG. 13 is a block diagram illustrating an invisible fence monitoringsystem according to another aspect of the present invention.

FIG. 14 is a pictorial diagram illustrating a boundary defining ageographical region for use with the invisible fence system of FIG. 13.

FIG. 15 is another pictorial diagram illustrating a defined regionhaving a closed boundary.

FIG. 16 is another pictorial diagram illustrating a defined regionincluding defined subdivisions.

FIG. 17 is a block diagram illustrating another aspect of the invisiblefence system.

FIG. 18 is a block diagram showing a fixed-location environmentalsensing system according to another aspect of the present invention.

FIG. 19 is a block diagram of a personal alarm system includingnavigational location in which the geometric dilution of precisioncalculations are done at the base station.

FIG. 20 is a block diagram showing an invisible fence alarm system inwhich the fence is stored and compared at the base station.

FIG. 21 is a block diagram illustrating a man-over-board alarm system.

FIG. 22 is a partial block diagram illustrating a one-way voice channelon a man-over-board alarm system.

FIG. 23 is a partial block diagram illustrating a two-way voice channelon a man-over-board alarm system.

FIG. 24 is a block diagram illustrating an invisible fence system.

FIG. 25 is a pictorial diagram illustrating geographical regions for aninvisible fence system.

FIG. 26 is a table defining a curfew for an invisible fence system.

FIG. 27 is a block diagram illustrating another embodiment of aninvisible fence system.

FIG. 28 is a partial block diagram illustrating a base station connectedto a communication channel via a modem.

FIG. 29 is a partial block diagram illustrating an alarm systemincluding an oil/chemical sensor, and all sensors activatingtransmission at a higher power level.

FIG. 30 is a block diagram illustrating another embodiment of a personalalarm system.

FIG. 31 is a partial block diagram illustrating specific circuits usedto select a transmission power level.

FIG. 32 is a partial block diagram illustrating other specific circuitsused to select a transmission power level.

FIG. 33 is a block diagram illustrating a specific embodiment of apersonal alarm system.

FIG. 34 is a block diagram illustrating a weather alarm system.

FIG. 35 is a pictorial diagram representing a specific embodiment of aweather region.

FIG. 36 is a pictorial diagram illustrating another specific embodimentof a weather region.

FIG. 37 is a partial block diagram illustrating a conditional activationof a navigational receiver for a weather alarm system.

FIG. 38 is a block diagram illustrating another specific embodiment of aweather alarm system.

FIG. 39 is a block diagram illustrating a specific embodiment of aremote monitoring unit.

FIG. 40 is a block diagram illustrating another specific embodiment of aremote monitoring unit.

FIG. 41 is a partial block diagram illustrating a plurality of sensorsin a specific embodiment of a remote monitoring unit.

FIG. 42 is a partial pictorial diagram illustrating a typical statusvector.

FIG. 43 is a partial block diagram illustrating an input deviceconnected for providing the value of a second variable in a specificembodiment of the invention.

FIG. 44 is a block diagram illustrating a specific embodiment of apersonal alarm system remote unit.

FIG. 45 is a block diagram illustrating a specific embodiment of a basestation for use with a remote unit such as shown in FIG. 44.

FIG. 46 is a block diagram of a personal alarm system according to oneaspect of the present invention.

FIG. 47 is a block diagram that illustrates another embodiment of apersonal alarm system remote unit.

FIG. 48 is a partial block diagram that illustrates the use of awireless phone within a personal alarm system remote unit according to aspecific embodiment of the present invention.

FIG. 49 is a partial block diagram illustrating the wireless phone ofFIG. 48 and including a circuit that automatically dials “911” fortransmitting the remote unit location.

FIG. 50 is a partial block diagram that illustrates the use of acellular telephone for transmitting the remote unit location and fortwo-way radio communication.

FIG. 51 is a partial block diagram that illustrates the use of a PCStelephone for transmitting the remote unit location and for two-wayradio communication.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to FIG. 1, there is shown a block diagram of a personalalarm system according to one embodiment of the present invention anddepicted generally by the numeral 10. The personal alarm system 10includes a remote unit 12 and a base station 14. The remote unit 12 hasa radio transmitter 16 and a receiver 18, and the base station 14 has aradio transmitter 20 and a receiver 22. The transmitters 16, 20 andreceivers 18, 22 are compatible for two-way radio communication betweenthe remote unit 12 and the base station 14.

In a preferred embodiment, the base station 14 includes an intervaltimer 24 which causes the transmitter 20 to transmit at predeterminedintervals. The receiver 18 of the remote unit 12 receives the signaltransmitted by the base station 14 and causes the transmitter 16 totransmit a response to complete an electronic handshake.

The remote unit transmitter 16 is capable of transmitting at an energyconserving low-power level or at an emergency high-power level. When thedistance between the remote unit 12 and the base station 14 exceeds apredetermined limit, the remote unit responds at the higher power level.

To accomplish the shift to the higher power level, the remote unitreceiver 18 generates a signal 26 which is proportional to the fieldstrength of the received signal, transmitted by the base station 14. Theremote unit 12 includes a comparitor 28 which compares the magnitude ofthe field strength signal 26 with a predetermined limit value 30 andgenerates a control signal 32.

The remote unit transmitter 16 is responsive to a circuit 34 forselecting transmission at either the low-power level or at thehigh-power level. The circuit 34 is connected to the control signal 32and selects transmission at the low-power level when the received fieldstrength equals or exceeds the limit value 30, and at the higher powerlevel when the received field strength is less than the limit value 30.Alternatively, the remote unit transmitter 16 transmits at one of aselectable plurality of transmission power levels. In anotheralternative embodiment, transmission is selectable within a continuousrange of transmission power levels.

Within an operating range of the personal alarm system 10, the fieldstrength of the base station 14 transmitted signal when received at theremote unit 12 is inversely proportional to the fourth power(approximately) of the distance between the two units. This distancedefines a ‘separation distance,’ and the predetermined limit value 30 isselected to cause transmission at the higher power level at a desiredseparation distance within the operating range.

In another embodiment, the remote unit 12 includes a hazard sensor 36which is connected to the transmitter 16. The hazard sensor 36 isselected to detect one of the following common hazards, water immersion,fire, smoke, excessive carbon monoxide concentration, and electricalshock. In one embodiment, a detected hazard causes the remote unit 12 totransmit a signal reporting the existence of the hazardous condition atthe moment the condition is detected. In another embodiment, thehazardous condition is reported when the response to the periodicelectronic handshake occurs.

In one embodiment, the base station 14 includes an audible alarm 38which is activated by the receiver 22. If the remote unit fails tocomplete the electronic handshake or reports a detected hazard orindicates it is out of range by sending an appropriate code, the basestation alarm 38 is activated to alert the operator.

FIG. 2 is a block diagram illustrating another embodiment of thepersonal alarm system of the present invention. The alarm system isindicated generally by the numeral 40 and includes a first remote unit42, a second remote unit 44 and a base station 46. The first remote unit42 includes a transmitter 48, a receiver 50, an identification number52, a received field strength signal 54, a comparitor 56, apredetermined limit value 58, a control signal 60, a power level selectcircuit 62 and a hazard sensor 64.

The second remote unit 44 includes a separate identification number 66,but is otherwise identical to the first remote unit 42.

The base station 46 includes a transmitter 68, an interval timer 70, areceiver 72, an alarm 74 and an ID-Status display 76.

In one embodiment of the invention illustrated in FIG. 2, the radiotransmission between the first remote unit 42 and the base station 46includes the identification number 52. The transmission between thesecond remote unit 44 and the base station 46 includes theidentification number 66. It will be understood by those skilled in theart that the system may include one or more remote units, each having adifferent identification number 52.

It will also be understood that each remote unit 42 may have a differentpredetermined limit value 58. The limit value 58 defines a distancebetween the remote unit 42 and the base station 46 beyond which theremote unit will transmit at its higher power level. If a number ofremote units are being used to monitor a group of children, in a schoolplayground for example, the limit values of each remote unit may be setto a value which will cause high power transmission if the child wandersoutside the playground area. In other applications, the limit value 58of each remote unit 42 may be set to a different value corresponding todifferent distances at which the individual remote units will switch tohigh power transmission.

In one embodiment, the base station 46 will provide an alarm 74 whenevera remote unit transmits at high power or reports the detection of ahazard. The identification number of the reporting remote unit and anindication of the type of hazard is displayed by the base station on theID-Status display 76. This information can be used by the operator, forexample a day-care provider, to decide what response is appropriate andwhether immediate caretaker notification is required. If a child hasmerely wandered out of range, the provider may simply send an associateout to get the child and return her to the play area. On the other hand,a water immersion hazard indication should prompt immediate notificationof caretakers and emergency personnel and immediate action by theday-care employees.

In another embodiment, the remote unit receiver 50 determines that theseparation distance between the remote unit 42 and the base station 46exceeds the predetermined threshold. The remote unit transmitter 48transmits a code or status bit to indicate that fact.

In an embodiment illustrated in FIG. 1, the polling message transmittedperiodically by the base station 14 is an RF carrier. The carrierfrequency is transmitted until a response from the remote unit 12 isreceived or until a watchdog timer (not illustrated) times out,resulting in an alarm The information contained in the remote unitresponse must include whether transmission is at low power or at highpower, and whether a hazard has been detected, since the base stationprovides an alarm in either of these instances.

In an embodiment illustrated in FIG. 2, however, additional informationmust be reported and the advantages of a digitally formatted remote unitresponse will be apparent to those possessing an ordinary level of skillin the art.

FIG. 3 is a block diagram illustrating another embodiment of thepersonal alarm system in accordance with the present invention andgenerally indicated by the numeral 80. Personal alarm system 80 includesa remote unit 82 and a base station 84.

The remote unit 82 includes a transmitter 86, a receiver 88, a powerlevel select circuit 90, an ID number 92, a visual beacon 94, an audiblebeacon 96, a watchdog timer 98, a plurality of hazard sensors 100including a water immersion sensor 102, a smoke sensor 104, a heatsensor 106, a carbon monoxide sensor 108, a tamper switch 109, and anelectrical shock sensor 110, an emergency switch (“panic button”) 112, abattery 113, and a ‘low battery power’ sensor 114.

The base station 84 includes a transmitter 116, a receiver 118 whichproduces a received field strength signal 120, a comparitor 122, apredetermined limit value 124, a comparitor output signal 126, aninterval timer 128, control signals 130 and 132, a visual alarm 134, anaudible alarm 136, an ID and Status display 138, a circuit 140 forinitiating a phone call and a connection 142 to the public telephonesystem.

The base station 84 and a plurality of the remote units 82 illustratedin the embodiment of FIG. 3 communicate using a digitally formattedmessage. One message format is used by the base station 84 to command aspecific remote unit 82, and a second message format is used by acommanded remote unit 82 to respond to the base station 84. Thesemessage formats are illustrated in FIGS. 5 and 4, respectively.

With reference to FIG. 4 there is shown a pictorial diagram of apreferred digital format for a response from a remote unit in a personalalarm system in accordance with the present invention, indicatedgenerally by the numeral 150. The digital response format 150 includes aremote unit ID number 152, a plurality of hazard sensor status bits 154including a water immersion status bit 156, a smoke sensor status bit158, a heat sensor status bit 160, an excessive carbon monoxideconcentration status bit 162, and an electrical shock status bit 164.The response 150 also includes a high power status bit, 166, a panicbutton status bit 168, a low battery power detector status bit 170, atamper switch status bit 171, and bits reserved for future applications172.

FIG. 5 is a pictorial diagram of a preferred digital format for a basestation to remote unit transmission, generally indicated by the numeral180. The digital message format 180 includes a command field 182 and aplurality of unassigned bits 190 reserved for a future application. Thecommand field 182 includes a coded field of bits 184 used to command aspecific remote unit to transmit its response message (using the format150). The command field 182 also includes a single bit 186 used tocommand a remote unit, such as the embodiment illustrated in FIG. 3, totransmit at high power. The command field 182 includes command bit 188used to command a remote unit to activate a beacon, such as the visualbeacon 94 and the audible beacon 96 illustrated in FIG. 3. The commandfield 182 also includes command bit 189, used to command a remote unitto activate a GPS receiver, such as illustrated in FIG. 6.

In an alternative embodiment, the remote unit transmitter is adapted totransmit at one of a plurality of transmission power levels and thesingle command bit 186 is replaced with a multi-bit command sub-fieldfor selection of a power level. In another embodiment, the remote unittransmitter is adapted to transmit at a power level selected from acontinuum of power levels and a multi-bit command sub-field is providedfor the power level selection.

Again with respect to FIG. 3, the Base station 84 periodically pollseach remote unit 82 by transmitting a command 180 requiring the remoteunit 82 to respond with message format 150. The polling is initiated bythe interval timer 128 which causes the base station transmitter 116 totransmit the outgoing message 180. The numerals 150 and 180 are used todesignate both the format of a message and the transmitted message. Aspecific reference to the format or the transmitted message will be usedwhen necessary for clarity. As is common in the communications industry,the message win sometimes be referred to as a ‘signal,’ at other timesas a ‘transmission,’ and as a ‘message;’ a distinction between thesewill be made when necessary for clarity.

The message 180 is received by all remote units and the remote unit towhich the message is directed (by the coded field 184) responds bytransmitting its identification number 152 and current status, bits154-170. The remote unit identification number 92 is connected to thetransmitter 86 for this purpose.

In the embodiment illustrated in FIG. 3, the function of measuringreceived field strength to determine whether a predetermined separationdistance is exceeded is performed in the base station 84. The basestation receiver 118 provides a received field strength signal 120 whichis connected to the comparitor 122. The predetermined limit value 124 isalso connected to the comparitor 122 which provides a comparitor outputsignal 126. If the received field strength 120 is less than the limitvalue 124, the comparitor output signal 126 is connected to assert the“go-to-high-power” command bit 186 in the base unit 84 outgoing message180. The limit value 124 is selected to establish the predeterminedseparation distance beyond which transmission at high power iscommanded.

In one embodiment, the selection of the limit value 124 is accomplishedby the manufacturer by entering the value into a read-only memorydevice. In another embodiment, the manufacturer uses manually operatedswitches to select the predetermined limit value 124. In anotherembodiment, the manufacturer installs jumper wires to select thepredetermined limit value 124. In yet another embodiment, the userselects a predetermined limit value 124 using manually operatedswitches.

The remote unit transmitter 86 is capable of transmitting at apower-conserving lower power level and also at an emergency higher powerlevel. Upon receiving a message 180 including the remote unitidentification number 184, the remote unit receiver passes the“go-to-high-power” command bit 186 to the power level select circuit 90which is connected to command the remote unit transmitter 86 to transmita response 150 at the higher power level. The response 150 includesstatus bit 166 used by the remote unit 82 to indicate that it istransmitting at high power.

In one embodiment, the remote unit includes the watchdog timer 98(designated a ‘No Signal Timeout’) which is reset by the receiver 88each time the remote unit 82 is polled. If no polling message 180 isreceived within the timeout period of the watchdog timer 98, the remoteunit transmitter 86 is commanded to transmit a non-polled message 150.

In one embodiment of the invention, the remote unit 82 includes amanually operated switch (“panic button”) 112 which is connected to thetransmitter 86 to command the transmission of a non-potted message 150.The panic button status bit 168 is set in the outgoing message 150 toindicate to the base station 84 that the panic button has beendepressed. Such a button can be used by a child or invalid or otherconcerned person to bring help.

In another embodiment, the remote unit includes a tamper switch 109which is activated if the remote unit is removed from the child, or isotherwise tampered with. The activation of the tamper switch 109 causesthe remote unit to transmit a code or status bit to the base unit toidentify the cause of the change of status (‘Tamper’ status bit 171illustrated in FIG. 4). In one related alternative, the remote unittransmits at the higher power level when the switch is activated byremoval of the remote unit from the child's person.

In another embodiment, the remote unit 82 includes a circuit 114 whichmonitors battery power. The circuit 114 is connected to initiate anon-polled message 150 if the circuit determines that battery power hasfallen below a predetermined power threshold. The message 150 willinclude the “low-battery-power” status bit 170. In an alternativeembodiment, a low battery power level will initiate a remote unittransmission at the higher power level (see FIG. 3).

In the embodiment illustrated in FIG. 3, the remote unit 82 includesseveral hazard sensors 100. These sensors are connected to report thedetection of common hazards and correspond to the sensor status bits 154in the remote unit response message 150.

In another embodiment of the present invention, the base stationreceiver 118 is connected to a visual alarm 134 and an audible alarm 136and will give an alarm when a message 150 is received which includes anyhazard sensor report 154 or any of the status bits 166-170.

The base station 84 also includes the status and ID display 138 used todisplay the status of all remote units in the personal alarm system 80.

In another embodiment of the personal alarm system 80, the base station84 includes a circuit 140 for initiating a telephone call when anemergency occurs. The circuit 140 includes the telephone numbers ofpersons to be notified in the event of an emergency. A connection 142 isprovided to a public landline or cellular telephone system. The circuit140 can place calls to personal paging devices, or alternatively placeprerecorded telephone messages to emergency personnel, such as thestandard “911” number.

FIG. 6 is a partial block diagram illustrating an embodiment of theinvention having a base station 200 and at least one remote unit 202.The partially illustrated remote unit 202 includes a transmitter 204,hazard sensors 201, 203, 205, a circuit 208 for causing the transmitterto transmit at a higher power level, a transmit interval timer 209, anda Global Positioning System (‘GPS’) receiver 210. The partiallyillustrated base station 200 includes a receiver 212, an alarm 213, adisplay 214 for displaying global positioning coordinates of longitudeand latitude, a circuit 216 for converting the global positioningcoordinates into predefined local coordinates, a map display 218 fordisplaying a map in the local coordinates and indicating the location ofthe remote unit 202, and a watchdog timer 219.

In a preferred embodiment of the alarm system, the remote unittransmitter 204 is connected to receive the global positioningcoordinates from the GPS receiver 210 for transmission to the basestation 200.

The GPS receiver 210 determines its position and provides that positionin global positioning coordinates to the transmitter 204. The globalposition coordinates of the remote unit 202 are transmitted to the basestation 200. The base station receiver 212 provides the received globalpositioning coordinates on line 222 to display 214 and to coordinateconverter 216. The display 214 displays the global coordinates in aworld-wide coordinate system such as longitude and latitude.

In one embodiment of the alarm system, the coordinate converter 216receives the global positioning coordinates from line 222 and convertsthese into a preferred local coordinate system A display 218 receivesthe converted coordinates and displays the location of the remote unit202 as a map for easy location of the transmitting remote unit 202.

In another embodiment of the alarm system the GPS receiver 210 includesa low power standby mode and a normal operating mode. The GPS receiver210 remains in the standby mode until a hazard is detected and thenswitches to the normal operating mode.

In another embodiment of the alarm system, the GPS receiver 210 remainsin the standby mode until commanded by the base station 200 to enter thenormal operating mode (see command bit 189 illustrated in FIG. 5).

In another embodiment of the alarm system, the remote unit transmitter204 is connected to the hazard sensors 201-205 for transmission ofdetected hazards. The base station receiver 212 is connected to activatethe alarm 213 upon detection of a hazard.

In one embodiment, a conventional electrical shock sensor 205 includes apair of electrical contacts 207 which are attached to the skin of a userfor detection of electrical shock.

In another embodiment, the remote unit 202 includes a transmit intervaltimer 209 and an ID number 211. The timer 209 is connected to cause theremote unit to transmit the ID number at predetermined intervals. Thebase station 200 includes a watchdog timer 219 adapted to activate thealarm 213 if the remote unit fails to transmit within the prescribedinterval.

In another embodiment of the alarm system, the remote unit 202 includesa carbon monoxide concentration sensor (see 108 of FIG. 3) having anoutput signal connected to activate a sensor status bit (see 162 of FIG.4) for transmission to the base station 200.

FIGS. 7-10 are pictorial illustrations of alternative embodiments of thepersonal alarm system of the present invention. FIG. 7 illustrates abase station 250 in two-way radio communication with a remote unit 252worn by a child. The child is running away from the base station 250such that the separation distance 256 has exceeded the preset threshold.The base station has determined that an alarm should be given, and anaudible alarm 254 is being sounded to alert a responsible caretaker.FIG. 8 illustrates a remote unit worn at the waist of a workman whoselocation and safety are being monitored. FIG. 9 illustrates a mobilebase station 270 equipped with a cigarette lighter adapter 272 foroperation in a vehicle. FIG. 10 illustrates a base station 280 adaptedfor operation from ordinary household current 282.

FIG. 11 is a block diagram which illustrates a man-over-board system inaccordance with one aspect of the present invention, and designatedgenerally by the numeral 300.

The man-over-board system 300 includes a remote unit 302, having anavigational receiver 304 and antenna 306 for receiving navigationalinformation, a sensor 308, having an output signal 310, a manuallyoperated switch 312, a radio transmitter 314 having an antenna 316. Theman-over-board system 300 also includes a base station 318 having aradio receiver 320 connected to an antenna 322 for receiving radiotransmissions from the remote unit 302. The base station 318 alsoincludes a display 324 for displaying the navigational location of theremote unit 302, a display 326 for displaying the status of the sensor308, a circuit 328 for comparing the field strength of the receivedradio transmission with a predetermined limit 330, and an alarm 332which is activated when the received field strength 334 falls below thevalue of the limit 330.

In use, the remote unit 302 is worn by a user and an alarm will be givenif the user falls over board and drifts too far from the boat. Thenavigational receiver 304 receives navigational information, as forexample from global positioning satellites 336. The navigationalreceiver 304 converts the navigational information into a location ofthe remote unit 302 and outputs the location 338 to the radiotransmitter 314 for transmission to the base station 318.

The sensor 308 provides an output signal 310 and defines a sensorstatus. The output signal 310 is connected to the radio transmitter 314for transmitting the sensor status to the base station 318.

The manually operated switch 312 includes an output 340 which isconnected to the radio transmitter 314 and permits the user to signalthe base station 318 by operating the switch 312. In a preferredembodiment, the manually operated switch 312 defines a panic button.

The radio receiver 320 provides three outputs, the received location 342of the remote unit 302, the received sensor status 344, and an outputsignal 334 proportional to the field strength of the received radiotransmission. As described above with respect to FIGS. 1-3, the remoteunit 302 and the base station 318 define a separation distance which isinversely proportional to the received field strength. The comparitorcircuit 328 compares the received field strength 334 with apredetermined limit 330 and produces an output signal 346 if the sign ofthe comparison is negative, indicating that the field strength of thereceived signal is less than the limit 330. If the user drifts beyond aseparation distance from the boat defined by the limit 330, the alarm332 is activated to alert the user's companions, who can then takeappropriate action.

In heavy seas or poor visibility, the base station 318 displays thecurrent location of the remote unit 302 on a suitable display 324. Thisis done in some appropriate coordinate system, such as standardlongitude and latitude. This feature permits the base station tomaintain contact with the man-over-board despite failure to maintaindirect eye contact.

FIG. 12 is a block diagram which illustrates a man-over-board systemincluding a two-way radio communication link and designated generally bythe numeral 350. The man-over-board system 350 includes a remote unit352 and a base station 354.

The remote unit 352 includes a navigational receiver 356, a radiotransmitter 358, a circuit 360 for causing the radio transmitter 358 totransmit at a high power level, a radio receiver 362, and circuits 364for activating a beacon.

The base station 354 includes a radio receiver 366, a radio transmitter368, a display 370 for displaying the location of the remote unit 352, acompactor circuit 372, a predetermined limit 374, an alarm 376, andcontrol circuits 378 for activating the radio transmitter 368.

The navigational receiver 356 is connected to an antenna 380 forreceiving navigational information, such as from global positioningsystem satellites (not shown). The receiver provides the location 382 ofthe remote unit 352 for radio transmission to the base station 354.

The remote unit radio transmitter 358 and radio receiver 362 areconnected to an antenna 384 for communication with the base station 354.The base station radio receiver 366 and radio transmitter 378 areconnected to an antenna 386 for communication with the remote unit 352.

The base station radio receiver 366 provides two outputs, the location388 of the remote unit for display by the location display 370, and asignal 390 whose value is inversely proportional to the field strengthof the signal received by the radio receiver 366.

The received field strength signal 390 and the predetermined limit 374are compared by the comparitor circuit 372 to determine whether theremote unit 352 is separated from the base station 354 by a distancegreater than the predetermined limit 374. An alarm 376 is given when theseparation distance exceeds the limit.

The control circuits 378 are used to cause the radio transmitter 368 tosend a control signal to the remote unit 352 for selecting high-powerremote unit radio transmission, or activating a visual or audible beaconfor use in locating the user in heavy seas or bad visibility.

FIG. 13 is a block diagram which illustrates an invisible fence formonitoring a movable subject and designated generally by the numeral400. The invisible fence 400 includes a remote unit 402 and a basestation 404 in one-way radio communication.

The remote unit 402 includes a navigational receiver 406, a radiotransmitter 408, storage circuits 410 for storing information defining ageographical region, a comparitor 412, second storage circuits 414 forstoring information defining a predetermined positional status, an alarm416, and a circuit 418 and having a pair of electrical contacts 420, 422for providing a mild electrical shock.

The base station 404 includes a radio receiver 424, a comparitor 426,storage circuits 428 for storing information defining a predeterminedpositional status, and an alarm 430.

In the embodiment illustrated in FIG. 13, the invisible fence 400defines a geographical region, for example the outer perimeter of anursing home in which elderly persons are cared for. If a particularpatient tends to wander away from the facility, creating an unusualburden upon the staff the remote unit 402 is attached to the patient'sclothing. If the patient wanders outside the defined perimeter, the basestation 404 alerts the staff before the patient has time to wander toofar from the nursing home.

Other applications are keeping a pet inside the yard, and applying amild electrical shock to the pet if it wanders too close to a definedperimeter. Attaching the remote unit 402 to a child and alerting thecaregiver in the event the child strays from a permitted area. Placingthe remote unit around the ankle of a person on parole or probation andgiving an alarm if the parolee strays from a permitted area. Theinvisible fence can also be used to monitor movement of inanimateobjects whose locations may change as the result of theft.

The remote unit navigational receiver 406 provides the location 432 ofthe remote unit. In a preferred embodiment, the storage circuits 410 areinplemented using ROM or RAM, as for example within an embeddedmicroprocessor. Consideration of FIGS. 14-16 is useful to anunderstanding of how the invisible fence operates.

FIGS. 14, 15 and 16 are pictorial diagrams illustrating boundaries usedto define geographical regions such as those used in a preferredembodiment of the invisible fence 400.

FIG. 14 shows a portion 440 of a city, including cross streets 442-454and a defining boundary 456. The boundary 456 divides the map 440 intotwo portions, one portion above boundary 456, the other portion below.

FIG. 15 shows a portion 460 of a city, including cross streets (notnumbered) and a closed boundary 462 made up of intersecting linesegments 464, 466, 468, 470, 472 and 474. The boundary 462 divides thecity map 460 into two subregions, one subregion defining an area 490wholly within the boundary 462, and the other subregion defining an area492 outside the boundary 462.

FIG. 16 shows a geographical region 480 which includes subregions 482and 484. Subregion 482 is entirely surrounded by subregion 484, whilesubregion 484 is enclosed within a pair of concentric closed boundaries486 and 488.

The information which defines these geographical regions and boundariesis stored in the storage circuits 410, and serve as one input to thecomparitor 412 (FIG. 13). The comparitor 412 also receives the locationoutput 432 from the navigational receiver 406. The comparitor 412compares the location of the remote unit 402 with the definedgeographical region and defines a relationship between the location andthe defined region which is expressed as a positional status. Thecomparitor 412 also receives an input from the second storage circuits414. These circuits store information defining a predeterminedpositional status.

Some examples will be useful in explaining how the positional status isused. Referring to FIG. 14, remote unit locations 494 and 496 areillustrated as dots, one location 494 being above the boundary 456, theother location 496 being below the boundary.

For the first example, assume that the location 494 is “within a definedgeographical region,” and that the location 496 is “outside the definedgeographical region.” Assume also that the predetermined positionalstatus is that “locations within the defined region are acceptable.”Next assume that the navigational receiver 406 reports the location 494for the remote unit. Then the comparitor 412 will define a positionalstatus that “the location of the remote unit relative to the definedregion is acceptable.” This positional status will be transmitted to thebase station 404 and will not result in activation of the alarm 430.

For the next example, assume that the navigational receiver 406 reportsthe location of the remote unit to be the location 496, and that theother assumptions remain the same. Then the comparitor 412 will define apositional status that “the location of the remote unit relative to thedefined region is not acceptable.” This positional status will betransmitted to the base station 404 and will result in activation of thealarm 430.

For the next example refer to FIG. 16 which includes three successivelocations 498, 500 and 502, shown linked by a broken line, as forexample by movement of the remote unit 402 from location 498 to location500 to location 502. Assume that the area outside the boundary 488defines an “acceptable” subregion. Assume further that the area betweenthe boundaries 488 and 486 defines a “warning” subregion. Also assumethat the area 482 inside the boundary 486 defines a “prohibited”subregion. Finally, assume that the navigational receiver 406 providesthree successive locations 498, 500 and 502.

In a preferred embodiment, and given these assumptions in the precedingparagraph, the comparitor 412 will determine that the location 498 isacceptable and will take no further action. The comparitor 412 willdetermine that the location 500 is within the warning subregion 484 andwill activate the remote unit alarm 416 to warn the person whosemovements are being monitored that he has entered a warning zone. Whenthe remote unit 402 arrives at the location 502, the comparitor 412 willdetermine that the remote unit has entered a prohibited zone and willactivate the mild electric shock circuit 418 which makes contact withthe skin of the monitored person through the electrical contacts 420,422. The positional status reported by the remote unit 402 for thesuccessive locations 498, 500 and 502 is “acceptable,” “warning given,”and “enforcement necessary,” respectively.

In another embodiment, no enforcement or warning are given by the remoteunit 402. Instead, as when used to monitor the movements of children orelderly patients, the positional status is transmitted to the basestation 404. There it is compared with a stored predetermined positionalstatus and used to set an alarm 430 if the positional status is notacceptable. The predetermined positional status is stored in storagecircuits 428 and the comparison is made by the comparitor 426.

The preferred embodiment for the storage and comparison circuits is theuse of an embedded microprocessor.

FIG. 17 is a block diagram illustrating a personal alarm system such asthe invisible fence of FIG. 13, and designated generally by the numeral520. Personal alarm system 520 includes a remote unit 522 and a basestation 524.

The remote unit 522 includes a radio transmitter 526 and a radioreceiver 528 connected to a shared antenna 530. The base station 524includes a radio receiver 532 and a radio transmitter 534 connected to ashared antenna 536 and defining a two-way communication link with theremote unit 522.

In one preferred embodiment, the communication link is direct betweenthe respective transmitters 526, 534 and the corresponding receivers528, 532. Other embodiments include access to existing commercial andprivate communications networks for completing the communication linkbetween the remote unit 522 and the base station 524. Typical networksinclude a cellular telephone network 538, a wireless communicationsnetwork 540, and a radio relay network 542.

FIG. 18 is a block diagram showing an environmental monitoring systemfor use in fixed locations, designated generally by the numeral 550. Theenvironmental monitoring system 550 includes a remote unit 552 and abase station 554.

The remote unit 552 includes storage circuits 556 for storinginformation defining the location of the remote unit 552, at least onesensor 558, a radio transmitter 560, and an antenna 562.

The base station 554 includes an antenna 564, a radio receiver 566, adisplay 568 for displaying the location of the remote unit 552, acomparitor 570, storage circuits 572 for storing information defining apredetermined sensor status, and an alarm 574.

The environmental monitoring system 550 is useful for applications inwhich the remote unit 552 remains in a fixed location which can beloaded into the storage circuits 556 when the remote unit 552 isactivated. Such applications would include use in forests for fireperimeter monitoring in which the sensor 558 was a heat sensor, or inmonitoring for oil spills when attached to a fixed buoy and the sensor558 detecting oil. Other useful applications include any application inwhich the location is known at the time of activation and in which somephysical parameter is to be measured or detected, such as smoke, motion,and mechanical stress. The environmental monitoring system 550 offers analternative to pre-assigned remote unit ID numbers, such as those usedin the systems illustrated in FIGS. 2 and 3.

The storage circuits 556 provide an output 576 defining the location ofthe remote unit 552. This output is connected to the radio transmitter560 for communication with the base station 554. The sensor 558 providesan output signal 578 defining a sensor status. The output signal isconnected to the radio transmitter 560 for communication of the sensorstatus to the base station 554.

The communications are received by the base station's radio receiver 566which provides outputs representing both the location 580 of the remoteunit 552 and the sensor status 582. The location 580 is connected to thedisplay 568 so that the location of the remote unit 552 can bedisplayed. The comparitor 570 receives the sensor status 582 and theinformation defining the predetermined sensor status which is stored inthe storage circuits 572. If the comparitor 570 determines that thesensor status indicates an alarm situation, it activates the alarm 574to alert a base station operator.

FIG. 19 is a block diagram which illustrates an alternative embodimentof a personal alarm system in which the remote unit transmitsdemodulated navigational and precise time-of-day information to the basestation, and the base station uses that information to compute thelocation of the remote unit. This alternative embodiment is designatedgenerally by the numeral 600 and includes a remote unit 602 and a basestation 604.

The remote unit 602 includes a navigational receiver 606, a demodulatorcircuit 608, a precise time-of-day circuit 610, a sensor 612, and aradio transmitter 614.

The base station 604 includes a radio receiver 616, computationalcircuits 618 for computing the location of the remote unit 602, adisplay 620 for displaying the computed location, a second display (canbe part of the first display) 622 for displaying a sensor status, acomparitor 624, storage circuits 626 for storing information defining apredetermined sensor status, and an alarm 628.

In a preferred embodiment, the navigational receiver 606 receivesnavigational information from global positioning system satellites (notshown). In this embodiment, the raw navigational information isdemodulated by the demodulator circuit 608 and the output of thedemodulator 608 is connected to the radio transmitter 614 forcommunication to the base station 604.

The precise time-of-day circuits 610 provide the time-of-day informationneeded to compute the actual location of the remote unit based upon thedemodulated navigational information. In the case of GPS navigationalinformation, geometric dilution of precision computations are done atthe base station 604 to derive the actual location of the remote unit602.

The sensor 612 provides an output signal defining a sensor status. Thedemodulated navigational information, the precise time-of-dayinformation and the sensor status are all connected to the radiotransmitter 614 for communication to the base station 604.

At the base station 604, the radio receiver 616 provides thenavigational and precise time-of-day information to the computationcircuits 618 for determining the actual location. In a preferredembodiment, the computation is made using an embedded microprocessor.The computed location is displayed using the display 620.

The radio receiver 616 also provides the received sensor status whichforms one input to the comparitor 624. Stored information defining apredetermined sensor status is provides by the storage circuits 626 as asecond input to the comparitor 624. If the received sensor status andthe stored sensor status do not agree, the comparitor 624 activates thealarm 628 to alert the base station operator.

FIG. 20 is a block diagram which illustrates an alternative embodimentof the invisible fence system in which the base station computes thelocation of the remote unit, and in which the fence definitions arestored at the base station rather than in the remote unit. Thealternative system is designated generally by the numeral 650 andincludes a remote unit 652 and a base station 654.

The remote unit 652 includes a navigational receiver 656, a demodulatorcircuit 658, a precise time-of-day circuit 660, a radio transmitter 662,a radio receiver 664, a shared antenna 666, and control status circuits668.

The base station 654 includes a radio receiver 670, a radio transmitter672, a shared antenna 674, computation circuits 676, storage circuits678, second storage circuits 680, a first comparitor 682, a secondcomparitor 684, a display 686, an alarm 688, and control circuits 690.

The navigational receiver 656 provides raw navigational information 692to the demodulator circuit 658. The demodulator circuit 658 demodulatesthe raw navigational information and provides demodulated navigationalinformation 694 to the radio transmitter 662 for communication to thebase station 654. The precise time-of-day circuit 660 providestime-of-day information 696 to the radio transmitter 662 forcommunication to the base station 654.

The base station radio receiver 670 provides received navigationalinformation 698 and received time-of-day information 700 to thecomputation circuits 676 for conversion to an actual location 702 of theremote unit 652. The storage circuits 678 store information defining ageographical region.

The first comparitor 682 receives the location 702 and the regiondefining information 704 and provides a positional status 706, asdescribed above with respect to FIGS. 13-16.

The second storage circuits 680 store information 708 defining apredetermined positional status. The second comparitor 684 receives thepositional status 706 and the predetermined positional status 708 andprovides control output signals 710 based upon the results of thepositional status comparison. When the location 702 is within a defined“warning” or “restricted” zone, the second comparitor 684 activates thealarm 688 and causes the location 702 to be displayed by the display686.

In one preferred embodiment, the remote unit includes circuits 668 whichprovide a means by which the base station 654 can warn the remote unituser or enforce a restriction, as for example, by applying the mildelectric shock of the embodiment shown in FIG. 13. The second comparitor684 uses a control signal 710 to activate the control circuits 690 tosend a command via the radio transmitter 672 to the remote unit 652 formodifying the remote unit control status. For example, if the remoteunit location is within a restricted zone, the base station 654 willcommand the remote unit 652 to provide an electric shock to enforce therestriction.

FIG. 21 is a block diagram illustrating another embodiment of aman-over-board alarm system, designated generally by the numeral 750.The man-over-board alarm system 750 includes a remote unit 752 and abase station 754.

The remote unit 752 includes a navigational receiver 756, a radiotransmitter 758, an environmental sensor 760, at least one manuallyoperated switch 762, a beacon 764, a circuit 766 for activating thenavigational receiver 756, and a control circuit 768.

The base station 754 includes a radio receiver 770, a remote-unitlocation display 772, a sensor status display 774, an alarm 776, aswitch status display 778, a control circuit 780, and storage 782 for apredetermined limit value.

The navigational receiver 756 receives navigational information via anantenna 757 and provides a location 759 of the remote unit to the radiotransmitter 758 for transmitting the remote unit location 759. Thenavigational receiver 756 has a normal operational mode and a low-powerstandby mode. In a preferred embodiment, the navigational receiver 756is normally in the low-power standby mode, thereby conserving operatingpower which is normally supplied by batteries.

The circuit 766 is responsive to the control circuit 768 for selectingthe operational mode and thereby “activating” the navigational receiver.In a specific embodiment, the control circuit 768 is responsive to ahazard sensor 760, such as a water-immersion sensor, for controlling thecircuit 766 to activate the navigational receiver 756. In anotherembodiment, the control circuit 768 is responsive to a manually operatedswitch 762, such as a manually operated panic button, for activating thenavigational receiver 756.

In a specific embodiment, the sensor 760 provides an output signal 761,and defines a sensor status. The manually operated switch 762 providesan output signal 763, and defines a switch status. The control circuit768 receives the sensor output signal 761 and the switch output signal763, and connects each to the radio transmitter 758 for communication ofthe sensor status and the switch status to the base station 754.

In another specific embodiment, the control circuit 768 is connected foractivating the remote unit beacon 764 in response to a change in thesensor status 761. In another embodiment, the control circuit 768activates the beacon 764 in response to a change in the switch status763. In one embodiment, the beacon 764 is a visual beacon, such as aflashing light. In another embodiment, the beacon 764 is an audiblebeacon which emits a periodic sound. The beacon 764 aids searchers inlocating a man-over-board.

In a specific embodiment, the control circuit 768 is implemented using aprogrammed micro-processor. In another specific embodiment, the controlcircuit 768 is implemented using an imbedded, programmedmicro-processor. In another embodiment, the control circuit 768 isimplemented using a programmed micro-controller.

The base-station radio receiver 770 receives the remote unit location759, the sensor status, and the switch status. The radio receiver 770 isconnected to the display 772 for displaying the received remote unitlocation, is connected to the display 774 for displaying the receivedsensor status, and is connected to the display 778 for displaying theswitch status. In a specific embodiment, the radio receiver 770 isconnected to the alarm 776 which is activated by a change in the sensorstatus, such as the detection of immersion in water. In another specificembodiment, the alarm is activated by a change in the switch status,such as a manual operation of the panic button.

The radio receiver 770 provides a signal 771 corresponding to a fieldstrength of a received radio communication. The control circuit 780compares the received field strength 771 with a predetermined limitvalue 783 provided by circuit 782. The control circuit 780 is connectedto activate the alarm 776 when the received field strength is less thanthe predetermined limit value 783. The received field strength 771, thecontrol circuit 780, and the predetermined limit value 783 define aseparation distance between the remote unit 752 and the base station754, as discussed above with respect to other embodiments of theinvention.

In a specific embodiment, the control circuit 780 and the circuit 782for providing the predetermined limit value 783 are implemented using aprogrammed micro-controller. In another specific embodiment, the circuit780 and the circuit 782 are implemented using an embedded, programmedmicro-controller. The functions performed by the circuits 780 and 782are performed in different embodiments alternatively by discreteintegrated circuits, by a programmed micro-controller, by an embedded,programmed micro-controller, by a programmed micro-processor, and by anembedded, programmed micro-processor.

In a specific embodiment of the man-over-board alarm system illustratedin FIG. 21, the sensor 760 includes a plurality of environmental,physiological and hazard sensors providing output signals and defining asensor status vector. In another specific embodiment, the sensor 760provides a plurality of output signals 761 defining another statusvector. In another specific embodiment, the sensor 760 provides ananalog output signal 761, and the control circuit 768 converts theanalog signal 761 for radio transmission as a sensor status vector. Thebase station 754 displays the sensor status vector using the display774.

In another specific embodiment of the man-over-board alarm systemillustrated in FIG. 21, the manually operated switch 762 includes aplurality of manually operated switches providing multiple outputsignals 763. The multiple output signals 763 define a switch statusvector which is connected to the control circuit 768 for radiotransmission to the base station 754. The base station 754 displays theswitch status vector using the display 778. In a specific embodiment,the remote unit manually operated switches 762 define a numeric keypad,and the base station 754 displays a manual entry made using the numerickeypad. In another specific embodiment, the manually operated switches762 define an alpha numeric keypad, and the base station 754 displaysmanually entered alpha numeric information.

FIG. 22 is a partial block diagram of the man-over-board alarm systemillustrated in FIG. 21, and designated generally by the numeral 800. Thealarm system 800 includes a remote unit 802 and a base station 804. Theremote unit 802 includes a radio transmitter 806 and a microphone 808.The base station 804 includes a radio receiver 810 and a speaker 812. Inthis embodiment of the alarm system 800, the microphone 808 is connectedto the transmitter 806 for defining a one-way voice radio communicationchannel with the base station receiver 810 and speaker 812. In aspecific embodiment, the radio transmitter 806 is also used to transmitthe remote unit location, the sensor status vector, and the switchstatus vector as discussed above with respect to FIG. 21. In anotherspecific embodiment, the radio receiver 810 is also used to receive theremote unit location, the sensor status vector, the switch statusvector, and to provide the received signal strength signal.

FIG. 23 is also a partial block diagram of the man-over-board alarmsystem shown in FIG. 21. The alarm system is designated generally by thenumeral 814. The alarm system 814 includes a remote unit 816 and a basestation 818. The remote unit 816 includes a radio transmitter 820, amicrophone 822, a radio receiver 824 and a speaker 826. The base station818 includes a radio receiver 828, a speaker 830, a radio transmitter832 and a microphone 834. These elements are configured to provide atwo-way voice communication channel between the remote unit 816 and thebase station 818. In a specific embodiment, the radio transmitter 820and radio receiver 828 are also used to communicate the remote unitlocation, the sensor status vector, and the switch status vector. Inanother specific embodiment, the radio receiver 828 also provides areceived signal strength signal.

FIG. 24 is a block diagram illustrating another embodiment of aninvisible fence system, designated generally by the numeral 850. Theinvisible fence system 850 includes a remote unit 852 and a base station854.

The remote unit 852 includes a navigational receiver 856, a radiotransmitter 858, a memory 860 for storing information defining ageographic region, a memory 862 for storing information defining apredetermined positional and time status, a circuit 863 for providingtime-of-day information, a comparison circuit 864, and an enforcementand alarm circuit 865.

The base station 854 includes a radio receiver 866, a memory 868 forstoring a predetermined positional and time status, a comparison circuit870 and an alarm 872.

The invisible fence system illustrated in FIG. 24 differs from theembodiment of FIG. 13 by providing an alarm and enforcement based uponboth time and location. The embodiment of FIG. 24 allows the defining ofzones of inclusion, and alternatively zones of exclusion, which aredefined in terms of location and time-of-day. For example, a paroleeequipped with the remote unit 852 may be confined to, and alternativelyexcluded from, a defined region between the hours of 6PM and 6AM. If theparolee leaves the region of confinement, or enters the region ofexclusion, between those two time limits, a radio transmission activatesthe alarm 872 at the base station 854, and simultaneously activates analarm and enforcement process 865 at the remote unit 852. In a specificembodiment, the parolee is first warned that he has left a region ofconfinement at an unallowed time. If the violation continues, theparolee is given a mild electrical shock. If the violation continues,the intensity of the electrical shock is increased. The authorities areput on notice by the base station alarm 872 that the parolee hasviolated his defined restrictions.

FIG. 25 is a pictorial diagram illustrating boundaries used to definegeographical regions such as those used in a preferred embodiment of theinvisible fence system 850. FIG. 25 shows a portion 1000 of a city,including cross streets (not numbered) and a closed boundary made up ofintersecting line segments 1006, 1008, 1010 and 1012. The boundarydivides the city map 1000 into two subregions, one subregion defining anarea 1002 wholly within the boundary, and the other subregion definingan area 1004 outside the boundary.

In a specific embodiment of an invisible fence system, such as thatillustrated in FIG. 24, a memory 860 stores information defining ageographical region, for example the region 1002. In an example of theoperation of the specific embodiment, assume the region 1002 representsa specific city block, surrounded by the city streets 1006, 1008, 1010and 1012. Further assume that a parolee is wearing the remote unit 852,and that the parolee is required by the terms of his parole to remainwithin the city block 1002 between the hours of 8PM and 7AM, and that atall other times the parolee is permitted to be outside the region 1002.

FIG. 26 is a table defining a relationship between the location of theremote unit 852 (FIG. 24) and the time-of-day for use in understanding acurfew feature of a specific embodiment of the invisible fence system850. Each row of the table represents a different location, and eachcolumn of the table represents a subdivision of the time-of-day. Therelationship defined by the table represents an example of a curfewrequiring the parolee (in the preceding example) to remain at home,i.e., within the city block 1002, between 8PM and 7AM. If the paroleeleaves home during the interval from 8PM to 7AM, an alarm 872 isactivated at the base station 854. The information represented by thetable is stored in a memory 862 in the remote unit 852, and is referredto as a ‘predetermined positional and time status.’

With respect to the specific embodiment illustrated in FIG. 24, thememory 860 stores information defining the geographical region 1002(FIG. 25). The comparison circuit 864 receives the remote unit location859, the time-of-day 861, the information defining the geographicalregion 1002, and the curfew defining information 867. The comparisoncircuit 864 compares the named items of information and provides apositional and time status 869 to the radio transmitter 858 forcommunication to the base station 854. In another embodiment of theinvisible fence system 850, the transmitter 858 periodically transmitsthe remote unit location 859 and time-of-day 861. This information isreceived at the base station 854 where the predetermined positional andtime status is stored in a memory 868. The base station 854 makes anindependent determination of whether or not the curfew is violated. Thepositional and time status is compared by circuit 870 with the receivedlocation and time-of-day information. An alarm 872 is given if theremote unit violates the established curfew.

FIG. 27 is a block diagram illustrating another embodiment of aninvisible fence system, designated generally by the numeral 1020. Theinvisible fence system 1020 includes a remote unit 1022 and a basestation 1024. The remote unit 1022 includes a navigational receiver1026, a radio transmitter 1028, a radio receiver 1030 and an enforcementand alarm circuit 1032. The base station 1024 includes a radio receiver1034, a radio transmitter 1036, a memory 1040 for storing informationdefining a geographical region, a memory 1042 for storing informationdefining a predetermined positional and time status, a display 1044 andan alarm 1046.

The navigational receiver 1026 provides information 1027 defining alocation of the remote unit 1022, and is connected to the remote unitradio transmitter 1028 for communicating the remote unit location to thebase station 1024. The transmitted remote unit location is received bythe base station radio receiver 1034 and provided on line 1035 to thecontrol/compare circuit 1038. The base station includes a circuit 1037for providing time-of-day information 1039 to the control/comparecircuit 1038.

In a specific embodiment, the control/compare circuit 1038 isimplemented as part of a programmed, imbeddedmicro-processor/micro-controller. A memory of the imbeddedmicro-processor provides the memory 1040 for storage of information 1041defining a geographical region, and the memory 1042 for storage ofinformation 1043 defining a predetermined positional and time status.The imbedded micro-processor implementation of the control/comparecircuit 1038 receives the remote unit location 1035, the time-of-day1039, the information 1041 defining a geographical region, and theinformation 1043 defining a predetermined positional and time status.

In the previous example, the defined geographical region corresponded tothe region 1002 (FIG. 25), and the predetermined positional and timestatus corresponded to the relationship defined by the table in FIG. 26.The parolee was required to be within the region 1002 between the hoursof 8PM and 7AM. The compare/control circuit 1038 compares the receivedinformation described above and determines whether the parolee is inviolation of the defined curfew. The parolee is in violation of thecurfew defined by the table in FIG. 26 when he is outside his homebetween the hours of 8PM and 7AM. In this example, the region 1002 (FIG.25) corresponds to the parolee's home. Locations outside region 1002 aretherefore outside his home. In this example, if the parolee is inviolation of the curfew, the control/compare circuit 1038 generates asignal 1045, connected to the base station radio transmitter 1036 foractivating an alarm/enforcement device 1032 at the remote unit 1022.Such a device and an alarm/enforcement protocol have been describedabove with respect to FIGS. 13 and 16.

In a specific embodiment of the invisible fence system shown in FIG. 27,the location of the remote unit is displayed 1044 at the base station1024. In one embodiment, the control/compare circuit 1038 continuouslydisplays the remote unit location. In another embodiment, thecontrol/compare circuit 1038 provides and alarm 1046 and displays theremote unit location when the parolee has violated the curfew.

In a specific embodiment of the invisible fence system of FIG. 27, thetime-o-day circuit 1037 is implemented as part of the imbeddedmicro-processor. When several remote units are transmitting theirlocations from different time zones, the base station time-of-day isadjusted at the base station to use the correct time-of-day for eachtransmitting remote unit. For a curfew type process, it is not necessarygenerally to use a precise time-of-day. However, when a precisetime-of-day is required, the remote unit transmitter is connected toreceive both a location and a precise time-of-day from the navigationalreceiver, or other precise time-of-day circuit, for transmission to thebase station. Such arrangements are illustrated in FIGS. 19, 20, 34 and36.

FIG. 28 is a partial block diagram illustrating an alarm system,designated generally by the numeral 1050. The alarm system 1050 includesa remote unit 1052 and a base station 1054 and is intended to berepresentative of many of the alarm systems in accordance with aspectsof this invention. The remote unit 1052 includes a radio transmitter1056 and a radio receiver 1058. The base station 1054 includes a modem1060. Through its modem 1060, the base station 1054 is connected to astandard communications channel, designated 1064 and a two-way radiolink 1062, permitting a two-way communication between the base station1054 and the remote unit 1052.

Such an arrangement provides a radio link for communicating with theremote unit 1052 while not requiring the base station 1054 to includethe necessary radio receiver and radio transmitter. In such a case, thebase station includes a communications receiver and a communicationstransmitter which in one embodiment includes a radio communicationsfacility and in another embodiment provides the modem capability. Themodem 1060 permits the base station to be connected via standard landline communications, such as a commercial telephone network. Thus thestandard communication channel 1064 includes a standard telephonenetwork, communications satellites, relay type radio links and othercommon carrier technologies such as cellular telephone, wirelesscommunications, and personal communications systems (“PCS”).

FIG. 29 is a partial block diagram illustrating an alternativeembodiment of the personal alarm system 80 as depicted in FIG. 3. Partsshown in FIG. 29 which correspond to parts shown in FIG. 3 have the sameidentification numerals.

FIG. 29 illustrates a radio transmitter 86, a circuit 90 for selecting atransmission power level for the transmitter 86. An oil/chemical sensor113 is added to the hazard sensors 100. Each sensor provides an outputsignal defining a sensor status. The sensor status of all sensors isconnected via a line 111 to the transmitter 86 for transmission of thesensor status. The output of each sensor 100 is connected via line 117to the selection circuit 90 for selecting a transmission power level.The transmitter 86 normally operates at a reduced power level toconserve battery power. When a hazard sensor 100 detects a hazardouscondition, the line 117 communicates that fact to the circuit 90 whichcauses the transmitter 86 to transmit at a higher power level.

FIG. 30 is a block diagram illustrating a specific embodiment of apersonal alarm system, designated generally by the numeral 1080, andincluding a remote unit 1082 and a base station 1084. The remote unit1082 includes a radio transmitter 1086, a radio receiver 1088, a controlcircuit 1090, a transmission power level selection circuit 1092 and asensor 1094. The base station 1084 includes a radio receiver 1096, aradio transmitter 1098, an alarm 1100 and a higher power level commandcircuit 1102.

FIG. 30 illustrates a system in which a sensor status 1095 istransmitted to the base station 1084 and generates an alarm 1100. Thecommand circuit 1102 is responsive to the received sensor status andcauses the base station transmitter 1098 to transmit a command to theremote unit 1082 causing the remote unit to transmit at a higher powerlevel. The command is received by the remote unit receiver 1088 and isinterpreted by the control circuit 1090 to select a higher powertransmission level 1092.

FIG. 31 is a partial block diagram illustrating a circuit 1130 includingan analog-to-digital converter 1132 and a read-only memory 1134. Theanalog-to-digital converter 1132 receives an analog input signal 1131and provides digital output signals 1133. The digital output signals1133 are connected to address input lines of the read-only-memory 1134.The read-only-memory provides digital output signals of storedinformation from an addressed memory location on output lines 1135.

The circuit shown in FIG. 31 is used to convert a received fieldstrength signal such as signal 771 in the base station 754 of FIG. 21,to a predetermined digital output vector on lines 1135.

FIG. 32 is a partial block diagram illustrating a digital-to-analogconverter 1140. The digital-to-analog converter 1140 receives digitalinput signals on lines 1141 and provides an analog output signal on line1142.

FIG. 33 is a block diagram illustrating an embodiment of a personalalarm system designated generally by the numeral 1150, and including aremote unit 1152 and a base station 1154. The remote unit 1152 includesa radio transmitter 1156, a radio receiver 1158, a circuit 1160 forselecting transmission power level and a sensor 1162. The base station1154 includes a radio receiver 1164, a radio transmitter 1166, an alarm1168 and a command control circuit 1170. The digital-to-analog converterillustrated in FIG. 32 is used in a specific embodiment of the circuit1160 of FIG. 33 for selecting one of a plurality of transmission powerlevels, as commanded by the base station. The base station receiver 1164provides a signal 1165 proportional to a received field strength. In aspecific embodiment, the signal 1165 is an analog signal and isconverted to a digital form using the conversion circuit 1130 of FIG.31. The digital output signals 1135 are used by the command controlcircuit 1170 to generate a power-level command 1171 for transmission tothe remote unit 1152. In one embodiment of the remote unit select powerlevel circuit 1160, the received digital power-level command is useddirectly to control the power level of the remote unit transmitter 1156.In another embodiment, the received power-level command is converted toan analog signal which is used to control the power level of the remoteunit transmitter 1156. In this manner, the alarm system is able tocompensate for an increase in separation distance, low remote unitbattery power or other conditions which cause the received signalstrength 1165 to be reduced. The circuits are also able to command areduction of the remote unit transmitting power level to conserve remoteunit battery power.

FIG. 34 is a block diagram illustrating a specific embodiment of aweather alarm system, designated generally by the numeral 1180. Theweather alarm system 1180 includes a remote unit 1182 and a base station1184.

The remote unit 1182 includes a navigational receiver 1186, a weatherreceiver 1188, a radio transmitter 1190, region defining circuits 1192,weather threshold defining circuits 1194, information combining circuits1196, and information comparison circuits 1198.

The base station 1184 includes a radio receiver 1200, a display circuit1202, and an alarm 1204.

The weather alarm system 1180 operates generally as follows, the remoteunit 1182 is deployed in the field, such as in a small, private aircraftand is used to monitor the weather within a zone surrounding theaircraft. As the aircraft moves, the zone surrounding the aircraft movesalso. A navigational receiver 1186 is used to determine the location ofthe aircraft at any point in time. A weather receiver 1188 receivesweather parameters broadcast by a Weather Surveillance Radar System ofthe US Weather Service, providing up-to-date weather information for theUnited States. The remote unit is programmed to monitor specific weatherparameters within the zone surrounding the aircraft and to compare thoseparameters with programmed limits. In the event that one or more of themonitored parameters exceeds the programmed limit, the remote unittransmitter 1190 is activated and transmits the location 1187 of theaircraft. In some embodiments, specific weather parameters are alsotransmitted. The base station 1184 receives the transmission, displays1202 the location and any transmitted weather parameters, and, ifappropriate, gives an alarm 1204.

FIG. 35 is a pictorial diagram illustrating an example of a weatherregion useful in understanding the operation of the weather alarm system1180 and similar embodiments. The weather region is designated generallyby the numeral 1220 and 1220 includes a region 1222 in which weatherparameters are received from a weather surveillance radar system. Withinthe region 1222 is a weather alarm system remote unit at a movinglocation 1224 and surrounded by a moving zone 1226 having a constantradius 1228. It is perhaps more relevant to state that at any point inthe contiguous 48 states of the lower continental United States theweather receiver 1188 receives weather parameters relevant to thecurrent location 1224 of the weather alarm system remote unit 1182 (theaircraft, in our example above). The aircraft is surrounded by a movingzone 1226 and the remote unit is monitoring specified weather parameterswithin the moving zone, notifying the base station 1184 when anymonitored parameter exceeds its programmed limit.

FIG. 36 is a pictorial diagram illustrating an example of anotherweather region, designated generally by the numeral 1240. In thisexample, the weather region 1240 includes an area of weather reporting1242. The aircraft is located at point 1244 and is moving in a directionand at a velocity shown by a vector 1246. In this example, the definedzone of weather parameter monitoring is 1248.

With respect once again to FIG. 34, the remote unit circuits 1192 areused to define the zone (1226 in FIG. 35, and 1248 in FIG. 26) which ismoving relative to the aircraft. In a specific embodiment, the circuits1192 are a memory portion of a programmed micro-controller, and the zoneis defined by information stored in the memory portion. The defined zoneis designated by the numeral 1193.

The remote unit circuits 1194 define specific weather parameters to bemonitored and also define specific threshold values, limits and rangesfor use in monitoring the weather parameters. The defined values aredesignated generally by the numeral 1195 and in a specific embodimentare stored in a memory portion of a programmed micro-controller.

As the aircraft proceeds on its flight, the navigational receiver 1186continues to provide a current location 1187, while the weather receiver1188 continues to provide current weather information 1189. The location1187 and the surrounding zone defining information 1193 are combined bycircuits 1196 and define a zone relative to the weather reporting region(1222 in the example of FIG. 35, and 1242 in the example of FIG. 36).This relative zone is compared by circuits 1198 with the receivedweather parameters 1189 and the selected weather parameters and limitvalues 1195 to determine whether or not any monitored parameter withinthe moving zone exceeds it limit. The line 1199 is used to activate theremote unit transmitter 1190 for transmitting the current location 1187and the result 1199 of the comparison.

FIG. 37 is a partial block diagram illustrating a specific embodiment ofa remote unit for a weather alarm system. The portion of the remote unitis designated generally by the numeral 1250, and includes a navigationalreceiver 1252, a circuit 1254 for defining an activation threshold, anda comparison circuit 1256. In the embodiment illustrated here, receivedweather parameters 1258 are compared with limit values, threshold valuesand ranges stored in the circuit 1254. If any specified weatherparameter exceeds its individual limit value, the comparison circuit1256 activates the navigational receiver 11252 which has been operatingin a standby mode. Since current location is not available until thenavigational receiver is activated, the received weather parameters 1258are not limited to a moving zone around the aircraft, but apply to theentire weather reporting region (1222 in the example of FIG. 35, and1242 in the example of FIG. 36). In a specific embodiment, the circuits1254 and 1256 are part of a programmed micro-controller.

FIG. 38 is a block diagram of another specific embodiment of a weatheralarm system, designated generally by the numeral 1270. The weatheralarm system 1270 includes a remote unit 1272 and a base station 1274.

The remote unit 1272 includes only a navigational receiver 1276,providing a current location to a radio transmitter 1278 fortransmission to a base station.

The base station 1274 includes a radio receiver 1280 for receiving thecurrent location 1281, a weather receiver 1282 for receiving weatherparameters, a region defining circuit 1284 for defining a zone relativeto the current remote unit location, a weather threshold definingcircuit 1286 for selecting specific weather parameters and for defininglimits, thresholds, and ranges for the each selected weather parameter,an information combining circuit 1288 for combining the current locationand the zone defining information, a comparison circuit 1290 forselecting the specified parameters within the zone relative to thecurrent location, comparing the selected parameters within the zone withtheir individual limits, and activating an alarm 1294 and displaying1292 the current location and comparison results when a monitoredweather parameter within the defined distance of the remote unit exceedsits limit, falls below its defined threshold, and falls inside/outsideof a defined range.

In the embodiment illustrated in FIG. 38 all the intelligence is placedinto the base station 1274, including the weather receiver 1282. In aspecific embodiment, the circuits 1284, 1286, 1288 and 1290 are part ofa programmed micro-controller.

FIG. 39 is a block diagram illustrating a self-locating remote alarmunit designated generally by the numeral 1300. The remote unit 1300includes a circuit 1302 defining a first variable and providing a value1303 for the first variable, a circuit 1304 defining a second variableand providing a value 1305 for the second variable, a communicationstransmitter 1306, a circuit 1308 defining a condition and providing avalue for the condition, a circuit 1310 for comparing the value of thefirst variable with the value of the condition, and a circuit 1312responsive to the comparison for enabling the communications transmitter1306 to transmit the value of the second variable and to transmit afunction of the value of the first variable.

Though the description of FIG. 39 is very abstract, the figurerepresents the essence of the major embodiments of the presentinvention, as the following examples will illustrate.

In a simple man-over-board monitor as illustrated in FIG. 11, the value310 of the first variable is provided by a sensor 308, the value 338 ofthe second variable is provided by a navigation receiver 304. When thesensor status 310 changes, a transmitter 314 transmits the remote unitlocation 338 and the sensor status 310.

In the same man-over-board monitor, when a panic button 312 isdepressed, the transmitter 314 transmits the remote unit location 338and the switch status 340.

In an environmental monitor illustrated in FIG. 18, the value of thefirst variable is a sensor status 578 for a monitored environmentalparameter, while the value of the second variable is a location 576 ofthe remote unit stored in a memory. When the sensor 558 detects apredetermined change in the monitored environmental parameter, thetransmitter 560 transmits the stored location of the remote unit and thesensor status 578. Alternatively, the remote unit 552 defines a patientmonitor, and the value of the second variable is stored information 556which identifies the patient, such as name, room and bed number, patientidentification code. The value of the first variable is the output of asensor 558 which monitors a physiological parameter, and defines asensor status 578. When a predetermined change in the monitoredphysiological parameter occurs, the transmitter 560 is activated andtransmits the patient identification information 576 as the value of thesecond variable and transmits and the sensor status 578 as the functionof the first variable.

The circuits 1308, 1310 and 1312 of FIG. 39 find their equivalents inthe man-over-board monitor, the patient monitor and in the environmentalmonitor in that a change in a sensor or switch status activates atransmission of the value of the second variable—dynamic location,patient ID, and static location, respectively—and a transmission of anappropriate function of the value of the first variable—sensor status.

In a man-over-board monitor 752 illustrated in FIG. 21, the value of thesecond variable is provided by a dynamic location determining device, inthis case the navigational receiver 756. Alternative embodiments use theWorld-wide LORAN navigation system, a satellite navigational system suchas the GPS system, and other alternative global and regionalnavigational systems for providing a value of the second variable whichis the location of the remote unit 752.

Another example of a remote unit represented by the block diagram inFIG. 39 is a remote weather alarm 1182 illustrated in FIG. 34 in whichthe value of the second variable is a remote unit location 1187, and inwhich the function of the first variable is defined by a circuit 1198 tobe the result 1199 of a comparison of a monitored weather parameter,within the defined zone relative to the weather alarm location 1187,with a defined weather threshold 1195.

Another example of the remote unit represented by FIG. 39 is aninvisible fence monitor 852 as illustrated in FIG. 24. The value of thesecond variable is a location 859 provided by a navigational receiver856, while the transmitted function of the first variable is apositional and time status 869, the result of a comparison by a circuit864 of the location 859, a time-of-day 861 and a defined curfew 860,862.

When a microphone 808 is connected to the remote unit transmitter 806,as shown in FIG. 22, the remote unit of FIG. 39 includes a one-way voicechannel.

FIG. 40 is a block diagram illustrating a remote alarm unit designatedgenerally by the numeral 1320. The remote unit 1320 includes a circuit1322 defining a first variable and providing a value 1323 for the firstvariable, a communications transmitter 1324, a circuit 1326 defining acondition and providing a value for the condition, a circuit 1328 forcomparing the value of the first variable with the value of thecondition, and a circuit 1330 responsive to the comparison for enablingthe communications transmitter 1324 to transmit a function of the value1323 of the first variable. The remote unit 1320 also includes acommunications receiver 1332 for defining a two-way communications link.

When the remote unit shown in FIG. 39 includes a communicationsreceiver, such as the receiver 1332 of FIG. 40, the communicationschannel is alternatively one of direct radio contact such as illustratedin a variety of the figures, wireless, cellular, radio telephone, radiorelay, to name a few representative communications channels as shown inFIGS. 17 and 28.

An example of a monitoring system such as illustrated in FIG. 40 isshown in FIGS. 3, 30 and 33. In each instance, one or more sensors andswitches provide the value for the first variable and the transmittedfunction of the value of the first variable is alternatively the sensorvalue and the sensor/switch status. The circuits 1326, 1328 and 1330find their equivalents in an activation of the transmitter upon a changeof the sensor/switch status. The remote monitoring system illustrated inFIG. 3 includes both a remote unit 82 of the class shown in FIG. 40 anda compatible base station 84.

FIG. 41 is a partial block diagram which illustrates a plurality ofsensor/switches designated by the numeral 1340. Each sensor/switch 1342provides an output signal 1343 defining a sensor/switch status. Atypical transmission format for a sensor/switch status and defining asensor/switch vector is shown in the partial pictorial diagram of FIG.42. The transmitted format is designated generally by the numeral 1350and includes a plurality of sensor/switch status bits 1352 defining astatus vector 1354. A portion 1356 of the transmitted format 1350 isunused and marked reserved.

Finally, FIG. 43 is a partial block diagram illustrating the temporaryconnection of an input device to a remote monitor of the type providinga stored value for the second variable. The figure includes theremovable input device 1350 temporarily connected to the remote monitor1362. The remote monitor 1362 includes a circuit 1364 for storing avalue for the second variable. The input device 1350 is connected to theremote monitor 1362 and supplies a value 1361 for storage in the circuit1364. Once the value 1361 has been stored, the input device 1360 isdisconnected from the remote monitor 1362, and the remote monitor usesthe value stored by the circuit 1364 as the value of the secondvariable. The remote monitor 1362 corresponds to the self-locatingremote alarm unit 1300 of FIG. 39, and the storage circuit 1364 of FIG.43 corresponds to the circuit 1304 of FIG. 39.

The two examples that are provided above for a self-locating remotealarm unit which provides a stored value for the second variable are theenvironmental monitor of FIG. 18 and its other embodiment, the patientmonitor. Both embodiments require that a value be provided for thesecond variable. A method for doing so is to connect an input device1360 to the remote monitor 1362, to use the input device to load a valuefor the second variable into the storage circuit 1364 (1304 of FIG. 39,and 556 of FIG. 18), then to disconnect the input device and to monitorthe specified environmental/physiological parameters. In one embodiment,the input device is a keypad of manually operated switches. The keypadis used to input an environmental monitor location, or, alternatively, apatient's ID information. In one embodiment of the procedure, anavigational receiver is used to provide a user with the environmentalmonitor location, which the user then enters by hand using the keypadinput device 1360 attached to the environmental monitor 1362 (552 ofFIG. 18). In another embodiment, the temporarily connected input device1360 is a navigational receiver and the location 1361 is stored in thestorage circuit 1364 (556 of FIG. 18, 1304 of FIG. 39). After thelocation has been stored in the storage circuit, the navigationalreceiver 1360 is disconnected and the environmental monitor left to doits job.

While the foregoing detailed description has described severalembodiments of the personal alarm system in accordance with thisinvention, it is to be understood that the above description isillustrative only and not limiting of the disclosed invention. Thus, theinvention is to be limited only by the claims as set forth below.

FIG. 44 is a block diagram illustrating a specific embodiment of apersonal alarm system remote unit. The remote unit is designatedgenerally by the reference numeral 1410, and includes a satellite globalpositioning receiver (navigational receiver) 1412, a radio transmitter1414, a sensor and threshold detector 1416, a microphone 1418, and avoice-activated detector 1420.

The navigational receiver 1412 receives positioning information fromgeo-synchronous satellites via antenna 1422, and provides a globallocation 1424 of the remote unit for transmission by the radiotransmitter 1414. The location 1424 is represented in appropriatecoordinates.

The sensor and threshold detector 1416 provides an output signal 1426that is activated when the sensor detects a condition that exceeds apredetermined threshold level. A variety of specific sensors iscontemplated, including but not limited to the following: a glucosesensor for monitoring the blood-glucose level of a patient; an oxygensensor for monitoring the oxygen level of the ambient air; a motionsensor for detecting movement in excess of a predetermined threshold; alight sensor for detecting ambient light in excess of a predeterminedthreshold; a liquid immersion sensor, a heat sensor for detectingtemperature in excess of a predetermined threshold; a carbon-monoxidesensor; and a smoke detector.

The microphone 1418 and the voice-activated detector 1420 provide anoutput signal 1430 that becomes active when the voice-activated detector1420 detects a predetermined spoken distress phrase such as “HELP!”

In a specific embodiment of the personal alarm system remote unit 1410,no sensor and threshold detector are included. In this embodiment, theradio transmitter 1414 is connected to transmit the remote unit location1424 when the voice-activated detector output signal 1430 is active.This specific embodiment of the invention permits the remote unit to beworn or carried by a person and the person's global location will betransmitted via antenna 1428 when a predetermined distress phrase isdetected.

In another specific embodiment of the personal alarm system remote unit1410, the sensor and threshold detector 1416 are included and thethreshold detector portion is disabled. The radio transmitter isconnected to transmit the sensor output signal (sensor status) 1426 whenthe remote unit location is transmitted. In yet another embodiment ofthe personal alarm system remote unit 1410, the threshold detector isenabled and the radio transmitter is connected for transmitting a sensorstatus 1426 and a remote unit location 1424 when either of the sensorand threshold detector output signal 1426 and the voice-activateddetector output signal 1430 is active.

In various specific embodiments, the navigational receiver is compatiblewith one of a geo-synchronous satellite global navigation system, theinfrastructure-based TDOA and RSSI systems, the SATNAV system, and theLORAN system. The preferred embodiment is that the navigational receiver1412 is compatible with the U.S. GPS system.

FIG. 45 is a block diagram illustrating a specific embodiment of a basestation for use with a remote unit such as shown in FIG. 44. The basestation is designated generally by the reference numeral 1432 andincludes an antenna 1434, a radio receiver 1436, a display 1440 fordisplaying the remote unit location, and an alarm 1442. In normal use,the radio receiver 1436 receives a radio transmission from a remote unitvia the antenna 1434. The radio receiver provides two output signals. Afirst output 1438 provides the global coordinates of the remote unitlocation for display while a second output 1439 becomes active when atransmission is received from a remote unit. The output 1439 is used toactivate the alarm 1442. In another specific embodiment of the basestation 1432, the output signal(s) 1438 includes both the remote unitlocation information and sensor status information.

FIG. 46 is a block diagram of a personal alarm system according toanother aspect of the present invention. The personal alarm system isdesignated generally by the reference numeral 1500 and includes a remoteunit 1502 and a base station 1504.

The remote unit 1502 includes a navigational receiver 1506, ademodulator circuit 1508, a precise time-of-day circuit 1510, avoice-activated detector circuit 1512, a microphone 1514, a radiotransmitter 1515, a navigational receiver antenna 1516, and a radiotransmitter antenna 1518.

The navigational receiver provides modulated navigational information1530 to the demodulator circuit 1508. The demodulator circuit 1508“demodulates” the modulated navigational information 1530 and providesdemodulated navigational information 1532 to the radio transmitter 1515.The precise time-of-day circuit 1510 provides a precise time-of-daysignal 1534 to the radio transmitter.

The microphone 1514 is connected to the voice-activated detector circuit1512 permitting the detector circuit 1512 to activate an output signal1536 when a predetermined distress phrase is detected, for example“HELP!”

The radio transmitter 1515 is connected to transmit the demodulatednavigational information 1532 and the precise time-of-day information1534 when the voice-activated output signal 1536 becomes active.

The base station 1504 includes an antenna 1520, a radio receiver 1522circuits 1524 for computing the remote unit location, a display 1526 andan alarm 1528.

Radio transmissions from the remote unit 1502 are received via theantenna 1520 and converted by the radio receiver into demodulatednavigational information 1538, and precise time-of-day information 1540.The circuits 1524 receive the demodulated navigational information andthe precise time-of-day information and compute a global location 1544for the transmitting remote unit 1502. The computed global location (inappropriate coordinates) is displayed on the display 1526. The alarm1528 is activated by a receiver output signal 1542 when a radiotransmission from the remote unit is received.

FIG. 47 is a block diagram that illustrates another embodiment of apersonal alarm system remote unit. The remote unit is designatedgenerally by the reference numeral 1600 and includes a navigationalantenna 1616, a navigational receiver 1602, a microphone 1610, avoice-activated detector 1604, a radio transmitter 1606 a radio antenna1618, a radio receiver 1608, and a speaker 1612.

The navigational receiver 1602 receives navigational information via thenavigational antenna 1616 and provides a location 1620 of the remoteunit in appropriate coordinates.

The microphone 1610 and the voice-activated detector 1604 are connectedto provide a Transmit Location signal 1628 that becomes active when thedetector 1604 recognizes an audible predetermined distress phrase suchas “HELP!” The radio transmitter 1606 is connected with the TransmitLocation signal 1628, and with the remote unit location information 1620so that the location information is transmitted when the signal 1628becomes active. Thus, in normal use, the remote unit 1600 transmits itsown location (in appropriate coordinates) when an audible, predetermineddistress phrase is detected. The predetermined distress phrase is presetto a specific language. In another embodiment, the predetermineddistress phrase is programmed into a programmable storage unit (notillustrated) that is connected with the voice-activated detector 1604.

The remote unit 1600 includes a switch 1614 that connects the microphone1610 with the radio transmitter 1606 for transmitting one-half of atwo-way radio communication. The switch 1614 also is connected togenerate a Transmit Voice signal 1626 that becomes active when theswitch 1614 is operated. The radio transmitter 1606 is connected withthe Transmit Voice signal 1628 so that when the switch is operated, themicrophone is connected for voice transmission in a push-to-talkarrangement (half-duplex mode), and the radio transmitter transmits thevoice via radio antenna 1618. The other half of the two-way radiocommunication is received by the radio antenna 1618, then converted toaudible sound by the radio receiver 1608 and the speaker 1612.

FIG. 48 is a partial block diagram that illustrates the use of awireless phone within a personal alarm system remote unit according to aspecific embodiment of the present invention. The personal alarm systemremote unit is designated generally by the reference numeral 1700, andincludes a wireless phone 1702, a wireless phone antenna 1704, remoteunit location information 1706, and a Transmit Location signal 1710.

The wireless phone 1702 typically includes elements necessary fortwo-way radio communication (full-duplex mode), such as a microphone(1610 of FIG. 47) and a speaker (1612 of FIG. 47).

When the Transmit Location signal 1710 becomes active, the wirelessphone 1702 transmits the remote unit location information 1706.

FIG. 49 is a partial block diagram illustrating the wireless phone ofFIG. 48 and including a circuit that automatically dials “911” fortransmitting the remote unit location. The wireless phone is designatedby the reference numeral 1720, while the circuit that automaticallydials “911” is designated by the reference numeral 1722. When theTransmit Location signal 1724 becomes active, the circuit 1722automatically dials the dedicated public safety help telephone number“911” via connection 1726 with the wireless phone 1720. Once thetelephone connection with the 911 service is established, the wirelessphone 1720 transmits the remote unit location information (1706 of FIG.48). Recently, additional public safety help telephone numbers have beencontemplated and, in some cases, assigned. A person having an ordinarylevel of skill in the relevant arts will appreciate that (1) the use ofthese additional telephone numbers is also contemplated by the presentinvention, and (2) a typical wireless phone includes a keypad permittinga user to place a call in the normal manner, including a call placed toa dedicated public safety help telephone number.

FIG. 50 is a partial block diagram that illustrates the use of acellular telephone 1730 for transmitting the remote unit location andfor two-way radio communication. In the illustrated embodiment, thewireless phone of FIGS. 48, 49 is the cellular telephone 1730. FIG. 51is a partial block diagram that illustrates the use of a PCS telephonefor transmitting the remote unit location and for two-way radiocommunication. In the illustrated embodiment, the wireless phone ofFIGS. 48, 49 is the PCS telephone 1740.

What is claimed is:
 1. A personal alarm system remote unit, comprising:a navigational receiver for providing a location of the remote unit; avoice-activated detector having an output signal that becomes activewhen a predetermined distress phrase is detected; and a radiotransmitter connected for transmitting the remote unit location when theoutput signal becomes active.
 2. The personal alarm system remote unitas set forth in claim 1, further including: a sensor having at least oneoutput signal and defining a sensor status; and the radio transmitteralso connected for transmitting the sensor status.
 3. The personal alarmsystem remote unit as set forth in claim 2, further including: athreshold detector connected for receiving the sensor at least oneoutput signal; and the radio transmitter also connected for transmittingthe remote unit location and the sensor status when the sensor outputexceeds a predetermined threshold as determined by the thresholddetector.
 4. A personal alarm system, comprising: a remote unitincluding, a navigational receiver for receiving navigationalinformation, a demodulator for demodulating the received navigationalinformation, timing circuits for providing precise time-of-dayinformation, a voice-activated detector having an output signal thatbecomes active when a predetermined distress phrase is detected, and aradio transmitter for transmitting the demodulated navigationalinformation and the precise time-of-day information when the detectoroutput signal becomes active; and a base station including, a radioreceiver for receiving the demodulated navigational information, and theprecise time-of-day information, computational means connected forcombining the received demodulated navigational information and theprecise time-of-day information to determine a location of the remoteunit, a display for displaying the location of the remote unit, and analarm activated by receipt of a transmission from the remote unit,whereby, the remote unit location is displayed and an alarm is activatedwhen the predetermined distress phrase is detected.
 5. The personalalarm system as set forth in claim 4, further including a microphoneconnected to the voice activated detector for receiving a distressphrase.
 6. A personal alarm system, comprising: a remote unit including,a navigational receiver for receiving navigational information defininga location of the remote unit, a voice-activated detector having anoutput signal that becomes active when a predetermined phrase isdetected, and a radio transmitter for transmitting the remote unitlocation when the output signal is active; and a base station including,a radio receiver for receiving the remote unit location, a display fordisplaying the location of the remote unit, and an alarm activated byreceipt of a transmission from the remote unit, whereby, the remote unitlocation is displayed and an alarm is activated when the predetermineddistress phrase is detected.
 7. The personal alarm system as set forthin claim 6, further including a microphone connected to the voiceactivated detector for receiving a distress phrase.
 8. A personal alarmsystem remote unit, comprising: a radio transmitter and radio receiverfor providing a two-way radio communication link; a navigationalreceiver for providing a location of the remote unit; a voice-activateddetector having an output signal activated by the detection of apredetermined distress phrase; the radio transmitter connected fortransmitting the remote unit location when the output signal isactivated; and a microphone and speaker connected with the radiotransmitter and receiver for providing a two-way voice channel via thetwo-way radio communication link.
 9. The personal alarm system remoteunit as set forth in claim 8, wherein the radio transmitter and receivercomprise a wireless telephone for use with a wireless telephone network.10. The personal alarm system remote unit as set forth in claim 9,further including means connected to the output signal for initiating awireless telephone call to a predetermined dedicated public safety helptelephone number.
 11. The personal alarm system remote unit as set forthin claim 10, wherein the predetermined number is the 911 dedicatedpublic safety help telephone number.
 12. The personal alarm systemremote unit as set forth in claim 9, wherein the wireless telephone is acellular telephone for use with a cellular telephone network.
 13. Thepersonal alarm system remote unit as set forth in claim 9, wherein thewireless telephone is a personal communications services telephone foroperation with a personal communications services telephone network. 14.A personal alarm system remote unit, comprising: a navigational receiverfor receiving navigational information; a demodulator for demodulatingthe received navigational information; timing circuits for providingprecise time-of-day information; a voice-activated detector having anoutput signal activated by the detection of a predetermined distressphrase; and a radio transmitted for transmitting the demodulatednavigational information, and the precise time-of-day information whenthe output signal is activated.
 15. The personal alarm system remoteunit as set forth in claim 14, further including: a sensor having atleast one output signal and defining a sensor status; and the radiotransmitter also connected for transmitting the sensor status.
 16. Thepersonal alarm system remote unit as set forth in claim 15, furtherincluding: a threshold detector connected for receiving the sensor atleast one output signal; and the radio transmitter also connected fortransmitting the remote unit location and the sensor status when thesensor output exceeds a predetermined threshold as determined by thethreshold detector.
 17. A personal alarm system remote unit, comprising:a radio transmitter and radio receiver for providing a two-way radiocommunication link; a navigational receiver for providing navigationalinformation; a demodulator for demodulating the received navigationalinformation; timing circuits for providing precise time-of-dayinformation; a voice-activated detector having an output signalactivated by the detection of a predetermined distress phrase; the radiotransmitter connected for transmitting the demodulated navigationalinformation, and the precise time-of-day information, when the outputsignal is activated; and a microphone and speaker connected with theradio transmitter and receiver for providing a two-way voice channel viathe two-way radio communication link.
 18. The personal alarm systemremote unit as set forth in claim 17, wherein the radio transmitter andreceiver comprise a wireless telephone for use with a wireless telephonenetwork.
 19. The personal alarm system remote unit as set forth in claim18, further including means connected to the output signal forinitiating a wireless telephone call to a predetermined dedicated publicsafety help telephone number.
 20. The personal alarm system remote unitas set forth in claim 19, wherein the predetermined number is the 911dedicated public safety help telephone number.
 21. The personal alarmsystem remote unit as set forth in claim 18, wherein the wirelesstelephone is a cellular telephone for use with a cellular telephonenetwork.
 22. The personal alarm system remote unit as set forth in claim18, wherein the wireless telephone is a personal communications servicestelephone for operation with a personal communications servicestelephone network.